CN-122013075-A - Preparation method of mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability

Abstract

The invention provides a preparation method of a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capacity, belonging to the technical field of aluminum alloy preparation. And sequentially carrying out homogenization treatment, upsetting forging and annealing treatment on the alloy blank to obtain the Al-Zn-Mg alloy with the mixed crystal structure. According to the mixed crystal structure Al-Zn-Mg alloy prepared by deformation and heat treatment, the grain refinement effect is remarkable, grain boundaries among grains are recombined, the fine grain structure enables sliding between atoms and the grain boundaries to occur more easily, the double-peak distribution characteristic is formed, fine grains provide higher strength, coarse grains are favorable for storing dislocation and promoting strain hardening, so that the uniform deformation capacity is improved, and the deformation resistance is reduced.

Inventors

• LI HUI
• HUANG ZHIQUAN
• CHANG CONG

Assignees

• 太原科技大学

Dates

Publication Date

20260512

Application Date

20260211

Claims (10)

1. 1. A preparation method of a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability is characterized by comprising the following steps of sequentially carrying out homogenization treatment, upsetting forging and annealing treatment on an alloy blank to obtain the mixed crystal structure Al-Zn-Mg alloy.
2. 2. The method for preparing a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability according to claim 1, wherein the homogenization treatment is carried out at a temperature of 465-475 ℃ for 22-26 hours.
3. 3. The method for preparing a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability according to claim 1 or 2, wherein the homogenized alloy blank is subjected to heating treatment before upsetting forging, wherein the heating treatment temperature is 310-460 ℃, and the heat preservation time is 1-3 h.
4. 4. The method for producing a mixed crystal structure Al-Zn-Mg alloy having a high plastic deformability according to claim 3, wherein the upsetting forging is a two-upsetting-one-drawing forging.
5. 5. The method for preparing the mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capacity according to claim 4, wherein the specific process of two upsetting and one drawing is that forging is firstly carried out along the X direction, then the mixed crystal structure Al-Zn-Mg alloy is rotated to be drawn along the Z direction, and then the mixed crystal structure Al-Zn-Mg alloy is forged along the Y direction.
6. 6. The method for producing a mixed crystal structure Al-Zn-Mg alloy having a high plastic deformation ability according to claim 3, wherein said upsetting forging is four upsetting three drawing.
7. 7. The method for preparing the mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capacity according to claim 6, wherein the specific process of four upsetting three drawing steps is as follows: (1) Firstly forging and pressing along the X direction, then drawing out along the Z direction by rotating, then forging and pressing along the Y direction, and carrying out intermediate annealing treatment after the forging and pressing are finished; (2) Continuously drawing out along the X direction after the intermediate annealing treatment, forging and pressing along the Z direction after rotating, drawing out along the Y direction, and carrying out the intermediate annealing treatment after the drawing out is finished; (3) Forging and pressing along the X direction again after the intermediate annealing treatment.
8. 8. The method for producing a mixed crystal structure Al-Zn-Mg alloy having a high plastic deformation ability according to claim 3, wherein the upsetting forging is seven upsetting six upsetting.
9. 9. The method for preparing the mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability according to claim 6, 7 or 8, wherein the temperature of the intermediate annealing treatment is 310-460 ℃ and the heat preservation time is 5-15 min in the upsetting forging process, and the deformation amount of forging drawing is 40-60% in each upsetting forging process.
10. 10. The method for preparing a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability according to claim 9, wherein the annealing treatment temperature is 450-470 ℃ and the heat preservation time is 0.5-1.5 h.

Description

Preparation method of mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability Technical Field The invention relates to the technical field of aluminum alloy preparation, in particular to a preparation method of a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability. Background The aluminum alloy is used as a lightweight structural material and has wide application prospect in the fields of aerospace, transportation, weaponry and the like. Among them, al-Zn-Mg alloy is an important development direction of high-strength aluminum alloy due to its higher specific strength and specific rigidity. However, while the conventional Al-Zn-Mg alloy is pursued to have high strength, the conventional Al-Zn-Mg alloy is often accompanied by the reduction of plasticity/toughness, and particularly faces the embarrassment of large deformation resistance and regional cracking when preparing complex components, so that the application of the conventional Al-Zn-Mg alloy under complex load conditions is limited. Therefore, how to greatly improve the plastic deformability of an alloy, particularly the formability at high temperature, on the basis of maintaining sufficient strength has become a core challenge in the current development of high-performance aluminum alloys. The appearance of heterogeneous materials (such as a bimodal grain structure, a gradient structure and the like) provides a new direction for the cooperative promotion of alloy strong plasticity, and the similar structure can obviously improve the integral plastic deformation capability of the material by introducing a multi-scale cooperative deformation mechanism. Among them, a mixed crystal structure having a bimodal distribution, i.e., a microstructure in which fine grains coexist with coarse grains, is considered as one of effective ways to achieve high plastic deformation ability. In this structure, fine grains can provide higher strength, while coarse grains can help store dislocations, promote strain hardening, and thus promote uniform deformability. However, how to prepare a mixed crystal structure with reasonable size matching, reasonable distribution and stable structure in an Al-Zn-Mg alloy can be controlled, and at present, significant technical difficulties still exist. In the prior art, severe plastic deformation (such as equal channel angular extrusion, high-pressure torsion and the like) is often adopted to refine grains, but the method often forms a uniform superfine crystal or nanocrystalline structure, so that ideal bimodal distribution is difficult to directly obtain, and the method has the advantages of complex equipment, high cost and limited sample size. On the other hand, the recrystallization process is regulated and controlled by heat treatment alone, and partial recrystallization structure can be formed, but the dependency on the initial structure state is strong, and the size matching and the spatial distribution of coarse and fine grains are difficult to control accurately. Particularly for Al-Zn-Mg alloy, the existence of coarse residual crystalline phase (such as Fe, si-containing intermetallic compound or coarse MgZn 2, etc.) in the as-cast structure can not only destroy the continuity of the matrix, but also seriously hinder the uniform refinement of crystal grains and the control of subsequent recrystallization behavior. Therefore, the development of a method which has relatively simple process, is suitable for large-size blanks, can effectively and synergistically regulate and control the microstructure of the Al-Zn-Mg alloy, particularly can eliminate harmful phases, refine a matrix and finally form a high-performance mixed crystal structure, and has important engineering significance for promoting the practical application of the Al-Zn-Mg alloy with low deformation resistance and excellent formability. Disclosure of Invention The invention aims to provide a preparation method of a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability, which aims to solve the problems of uneven distribution of the mixed crystal structure of the Al-Zn-Mg alloy and poor high-temperature plastic deformation capability in the prior art. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a preparation method of a mixed crystal structure Al-Zn-Mg alloy with high plastic deformation capability, which comprises the following steps of sequentially carrying out homogenization treatment, upsetting forging and annealing treatment on an alloy blank to obtain the mixed crystal structure Al-Zn-Mg alloy. Preferably, the homogenization treatment is carried out at a temperature of 465-475 ℃ for 22-26 hours. Preferably, the homogenized alloy blank is subjected to heat treatment before upsetting forging, wherein the temperature of the heat treatment is 310-460 ℃, and the heat preservation time is 1-3 h. Preferably